Abstract 10867: The Best Predictor of Responders to Cardiac Resynchronization Therapy Can be Acute Improvement of Left Ventricular Relaxation
[Introduction] Cardiac Resynchronization therapy (CRT) is an efficacious treatment especially in patients with drug-refractory heart failure. To predict responders to CRT, many studies have been conducted. However, the established index has not been proven yet. The objective of this study was to assess the hypothesis that improvement of left ventricular (LV) invasive hemodynamic parameter can determine responders to CRT.
[Methods] The patients who underwent CRT were enrolled (n=34, age; 69±9 year, male; 24, left bundle branch block; 17, QRS duration; 146±20ms). The LV pressure waveforms were recorded in all cases before CRT implantation by using 5Fr manometer-tipped catheter in the condition of both biventricular pacing on/off. The LV hemodynamic parameters were analyzed, and the rate of improvement regarding each parameter by biventricular pacing was calculated. CRT responder was defined as a patient with more than 15% decrease in LV end-systolic volume at 6-month follow-up. We compared the acute LV hemodynamical improvements in responders and those in non-responders.
[Results] In this study, 19 patients (55%) were classified as responders. Each LV hemodynamic parameter at baseline was similar between both groups. LV contractile index, LV dP/dt(+) intended the greater improvement in responders, but not statistically significant (16.4±15.9 vs 8.6±15.2 %; p=0.17). Regarding LV relaxation index, both LV dp/dt(-) and time constant (Tau) in responders showed significantly greater improvements than those in non-responders (18.1±16.2 vs -1.7±10.3 %; p=0.02 , -12.2±8.3 vs 6.6±8.0 %; p<0.0001). The area under receiver operator characteristic curve was 0.92 for the index of shortening of Tau, which was better than any other hemodynamic index. The cutoff value of more than 3% shortening of Tau predicted responders with 80% sensitivity and 94% specificity. Furthermore, the multivariate analysis revealed that this improvement of Tau by more than 3% was the strongest predictive factor for determining CRT responders (odds ratio; 25.9, 95% confidence interval; 1.6-431.5, p=0.02).
[Conclusion] Our findings suggest that the extent of the improvement in LV relaxation assessed by Tau in the acute phase might be a superior predictor of favorable response to CRT.
- © 2012 by American Heart Association, Inc.